It is generally recognised by commentators and researchers that the next significant frontier in agriculture is the formulation and application of precision agricultural techniques. Precision agriculture means the collection of site-specific information, application of that site-specific information in site-specific analysis, and the subsequent making of decisions in truly site-specific manner.
Fundamental to the philosophy of precision agriculture is the concept of matching site-specific inputs to site-specific needs; if a part of a field needs more fertilizer, give that part more fertilizer; if a section of a crop needs harvesting early, harvest it early. These are simple, common-sense ideas. However, like many good ideas, there is a significant gap between theory and implementation. The use of management zones is currently the most practical way to implement the theory of precision agriculture. However, this is not truly precision agriculture, as the size of the zones and the process of data collection necessarily involves a relatively significant degree of averaging which in turn impacts on how site-specific decision making can be.
One critical area ripe for application of precision agriculture techniques is in feed budgeting systems. Dairy commentators and researchers have suggested that by the use of such systems a net improvement in pasture utilisation of between 10-15% may be possible. Using current production costs and returns, including costs associated with increased stocking rate as at the present date estimates, indications are that for New Zealand in 2005 NZ$ terms a 10% improvement correlates to an improvement of some $559 million, with a 15% improvement correlating to an $871 million increase.
The gains are based on assumptions that a number of contributing factors will align. One of the more obvious primary contributors is the fact that farmers would be in a position to develop a budgeting approach and make better decisions regarding feed, production and use, but there are other short and long term benefits.
Short term benefits include being able to more accurately place break fences and in the calculation of the amount of supplementary feed required, which would mean that cows are less likely to be underfed, which is detrimental to production, or overfed, which is wasteful of resources.
Longer term benefits centre around the ability to identify areas or zones within a paddock that are less productive than others, or have less palatable grass. This means that application of fertilisers, weed sprays, drainage, irrigation, over sowing of pasture etc could be targeted at those particular zones.
One of the main problems with being able to implement a system of precision pasture management relates to the difficulty of securing an adequate method of pasture measurement. More specific problems include difficulties with obtaining accurate individual measurements or samples, and with obtaining sufficient samples that will allow variability to be taken into account.
One of the more common methods of pasture measurement today involves the use of a rising plate meter. There is little intrinsically wrong with rising plate meter measurements as a means of pasture measurement. The problem is that they are slow to use, and so take considerable time to provide enough samples to form an accurate picture of production, and because fewer readings are inherently taken considerable care must be employed to make sure that any readings which are taken are truly representative of the paddock being measured.
Fewer samples also give rise to significant potential for errors to creep in, and for any errors to become amplified in their impact.
A typical error is of the kind generated when the point of measurement is not representative of the paddock—a particular problem with pasture which is heavily pugged conditions—for example, depending on the total number of readings taken, a reading from the base of a 75 mm hoof print could theoretically have the effect of erroneously adding 920 kg of dry matter to the plate reading (Assuming 120 kgDMha-1 per cm of plate height). Operator error is thus a significant contributing factor.
Errors become more important when measuring growth rates, the shorter the time interval between measurements the worse the problem and the more important is the repeatability of measurement.
Further, because of the time consuming nature of doing a pasture cover analysis using a rising plate meter, they are typically done at best every 10 days or so. As a result only a “snapshot” in time of pasture cover is measured. However, such a “snapshot” allows a feed wedge to be determined from the data derived which can indicate an upcoming feed surplus or shortage in the next few weeks.
What is not practically possible with a rising plate meter because of the time taken to complete, but which would be extremely beneficial, is a set of pasture pre-grazing measurements taken just before grazing a paddock, and a second set just after grazing a paddock to establish the residual pasture cover, thereby allowing total grass grown between grazings to be calculated, along with the average kilograms of dry matter consumed by each animal to be derived after the fact.
There is clearly a need for an improved method and means for pasture measurement to realise the significant benefits that precision pasture management offers, and it is an object of the present invention to provide such an improved method and means, and consequently an improved method and system of pasture management, or at least to provide the public with a useful choice.